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Optimize block type decoding in 10G PHY RX to reduce fanin
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Signed-off-by: Alex Forencich <alex@alexforencich.com>
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@alexforencich
alexforencich committed Jan 15, 2024
1 parent 74936e8 commit f08eb74
Showing 1 changed file with 47 additions and 18 deletions.
65 changes: 47 additions & 18 deletions rtl/xgmii_baser_dec_64.v
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Original file line number Diff line number Diff line change
Expand Up @@ -199,19 +199,20 @@ always @* begin
endcase
end

if (encoded_rx_hdr == SYNC_DATA) begin
// use only four bits of block type for reduced fanin
if (encoded_rx_hdr[0] == 0) begin
xgmii_rxd_next = encoded_rx_data;
xgmii_rxc_next = 8'h00;
rx_bad_block_next = 1'b0;
end else if (encoded_rx_hdr == SYNC_CTRL) begin
case (encoded_rx_data[7:0])
BLOCK_TYPE_CTRL: begin
end else begin
case (encoded_rx_data[7:4])
BLOCK_TYPE_CTRL[7:4]: begin
// C7 C6 C5 C4 C3 C2 C1 C0 BT
xgmii_rxd_next = decoded_ctrl;
xgmii_rxc_next = 8'hff;
rx_bad_block_next = decode_err != 0;
end
BLOCK_TYPE_OS_4: begin
BLOCK_TYPE_OS_4[7:4]: begin
// D7 D6 D5 O4 C3 C2 C1 C0 BT
xgmii_rxd_next[31:0] = decoded_ctrl[31:0];
xgmii_rxc_next[3:0] = 4'hf;
Expand All @@ -225,15 +226,15 @@ always @* begin
rx_bad_block_next = 1'b1;
end
end
BLOCK_TYPE_START_4: begin
BLOCK_TYPE_START_4[7:4]: begin
// D7 D6 D5 C3 C2 C1 C0 BT
xgmii_rxd_next = {encoded_rx_data[63:40], XGMII_START, decoded_ctrl[31:0]};
xgmii_rxc_next = 8'h1f;
rx_bad_block_next = decode_err[3:0] != 0;
rx_sequence_error_next = frame_reg;
frame_next = 1'b1;
end
BLOCK_TYPE_OS_START: begin
BLOCK_TYPE_OS_START[7:4]: begin
// D7 D6 D5 O0 D3 D2 D1 BT
xgmii_rxd_next[31:8] = encoded_rx_data[31:8];
xgmii_rxc_next[3:0] = 4'hf;
Expand All @@ -249,7 +250,7 @@ always @* begin
rx_sequence_error_next = frame_reg;
frame_next = 1'b1;
end
BLOCK_TYPE_OS_04: begin
BLOCK_TYPE_OS_04[7:4]: begin
// D7 D6 D5 O4 O0 D3 D2 D1 BT
rx_bad_block_next = 1'b0;
xgmii_rxd_next[31:8] = encoded_rx_data[31:8];
Expand All @@ -269,15 +270,15 @@ always @* begin
rx_bad_block_next = 1'b1;
end
end
BLOCK_TYPE_START_0: begin
BLOCK_TYPE_START_0[7:4]: begin
// D7 D6 D5 D4 D3 D2 D1 BT
xgmii_rxd_next = {encoded_rx_data[63:8], XGMII_START};
xgmii_rxc_next = 8'h01;
rx_bad_block_next = 1'b0;
rx_sequence_error_next = frame_reg;
frame_next = 1'b1;
end
BLOCK_TYPE_OS_0: begin
BLOCK_TYPE_OS_0[7:4]: begin
// C7 C6 C5 C4 O0 D3 D2 D1 BT
xgmii_rxd_next[31:8] = encoded_rx_data[31:8];
xgmii_rxc_next[3:0] = 4'h1;
Expand All @@ -291,63 +292,63 @@ always @* begin
xgmii_rxd_next[63:32] = decoded_ctrl[63:32];
xgmii_rxc_next[7:4] = 4'hf;
end
BLOCK_TYPE_TERM_0: begin
BLOCK_TYPE_TERM_0[7:4]: begin
// C7 C6 C5 C4 C3 C2 C1 BT
xgmii_rxd_next = {decoded_ctrl[63:8], XGMII_TERM};
xgmii_rxc_next = 8'hff;
rx_bad_block_next = decode_err[7:1] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_1: begin
BLOCK_TYPE_TERM_1[7:4]: begin
// C7 C6 C5 C4 C3 C2 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:16], XGMII_TERM, encoded_rx_data[15:8]};
xgmii_rxc_next = 8'hfe;
rx_bad_block_next = decode_err[7:2] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_2: begin
BLOCK_TYPE_TERM_2[7:4]: begin
// C7 C6 C5 C4 C3 D1 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:24], XGMII_TERM, encoded_rx_data[23:8]};
xgmii_rxc_next = 8'hfc;
rx_bad_block_next = decode_err[7:3] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_3: begin
BLOCK_TYPE_TERM_3[7:4]: begin
// C7 C6 C5 C4 D2 D1 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:32], XGMII_TERM, encoded_rx_data[31:8]};
xgmii_rxc_next = 8'hf8;
rx_bad_block_next = decode_err[7:4] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_4: begin
BLOCK_TYPE_TERM_4[7:4]: begin
// C7 C6 C5 D3 D2 D1 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:40], XGMII_TERM, encoded_rx_data[39:8]};
xgmii_rxc_next = 8'hf0;
rx_bad_block_next = decode_err[7:5] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_5: begin
BLOCK_TYPE_TERM_5[7:4]: begin
// C7 C6 D4 D3 D2 D1 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:48], XGMII_TERM, encoded_rx_data[47:8]};
xgmii_rxc_next = 8'he0;
rx_bad_block_next = decode_err[7:6] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_6: begin
BLOCK_TYPE_TERM_6[7:4]: begin
// C7 D5 D4 D3 D2 D1 D0 BT
xgmii_rxd_next = {decoded_ctrl[63:56], XGMII_TERM, encoded_rx_data[55:8]};
xgmii_rxc_next = 8'hc0;
rx_bad_block_next = decode_err[7] != 0;
rx_sequence_error_next = !frame_reg;
frame_next = 1'b0;
end
BLOCK_TYPE_TERM_7: begin
BLOCK_TYPE_TERM_7[7:4]: begin
// D6 D5 D4 D3 D2 D1 D0 BT
xgmii_rxd_next = {XGMII_TERM, encoded_rx_data[63:8]};
xgmii_rxc_next = 8'h80;
Expand All @@ -362,6 +363,34 @@ always @* begin
rx_bad_block_next = 1'b1;
end
endcase
end

// check all block type bits to detect bad encodings
if (encoded_rx_hdr == SYNC_DATA) begin
end else if (encoded_rx_hdr == SYNC_CTRL) begin
case (encoded_rx_data[7:0])
BLOCK_TYPE_CTRL: begin end
BLOCK_TYPE_OS_4: begin end
BLOCK_TYPE_START_4: begin end
BLOCK_TYPE_OS_START: begin end
BLOCK_TYPE_OS_04: begin end
BLOCK_TYPE_START_0: begin end
BLOCK_TYPE_OS_0: begin end
BLOCK_TYPE_TERM_0: begin end
BLOCK_TYPE_TERM_1: begin end
BLOCK_TYPE_TERM_2: begin end
BLOCK_TYPE_TERM_3: begin end
BLOCK_TYPE_TERM_4: begin end
BLOCK_TYPE_TERM_5: begin end
BLOCK_TYPE_TERM_6: begin end
BLOCK_TYPE_TERM_7: begin end
default: begin
// invalid block type
xgmii_rxd_next = {8{XGMII_ERROR}};
xgmii_rxc_next = 8'hff;
rx_bad_block_next = 1'b1;
end
endcase
end else begin
// invalid header
xgmii_rxd_next = {8{XGMII_ERROR}};
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